CNN — CDK Global, a software firm serving car dealerships across the US that was roiled by a cyberattack last month, appears to have paid a $25 million ransom to the hackers, multiple sources familiar with the matter told CNN. The company has declined to discuss the matter. Pinpointing exactly who sends a cryptocurrency payment can be complicated by the relative anonymity that some crypto services offer. But data on the blockchain that underpins cryptocurrency payments also tells its own story. ...